Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Vapor-liquid equilibria at (333.15, 343.15, and 353.15) K for seven binary mixtures of benzene + nonane, methylbenzene + 1,2-dimethylbenzene, 1,3-dimethylbenzene + 2,3,4,5-tetrahydrothiophene-1,1-dioxide, 1,2-dimethylbenzene + 2,3,4,5-tetrahydrothiophene-1,1-dioxide, 1,2-dimethylbenzene + N-methylformamide (NMF), 1,3-dimethylbenzene + NMF, and 1,4-dimethylbenzene + NMF have been obtained at pressures ranging from (0.01 to 101.3) kPa. The Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models have been employed to correlate experimental data to find intermolecular parameters. The nonideal behavior of the vapor phase has been considered by using the Peng-Robinson equation of state in calculating the vapor mole fraction. Liquid and vapor densities were measured by using two vibrating tube densitometers to determine liquid excess molar volumes. Six systems of benzene + nonane, 1,3-dimethylbenzene + 2,3,4,5-tetrahydrothiophene-1,1-dioxide, 1,2-dimethylbenzene + 2,3,4,5-tetrahydrothiophene-1,1-dioxide, 1,2-dimethylbenzene + NMF, 1,3-dimethylbenzene + NMF, and 1,4-dimethylbenzene + NMF mixtures present large positive deviations from the ideal solution and belong to endothermic mixtures because their excess Gibbs energies are positive. Only one system of the methylbenzene + 1,2-dimethylbenzene mixture may present a slight exothermic mixing deviation from the ideal solution. Temperature-dependent intermolecular parameters in the three models were obtained in this study.